1. Field of the Invention
Example embodiments generally relate to a fixing device and an image forming apparatus, and more particularly, to a fixing device for fixing an image on a recording medium and an image forming apparatus incorporating the fixing device.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, or multifunction printers having at least one of copying, printing, scanning, and facsimile functions, typically form an image on a recording medium according to image data. Thus, for example, a charger uniformly charges a surface of a photoconductor; an optical writer emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a development device supplies toner to the electrostatic latent image formed on the photoconductor to render the electrostatic latent image visible as a toner image; the toner image is directly transferred from the photoconductor onto a recording medium or is indirectly transferred from the photoconductor onto a recording medium via an intermediate transfer belt; finally, a fixing device applies heat and pressure to the recording medium bearing the toner image to fix the toner image on the recording medium, thus forming the image on the recording medium.
Such fixing device may include a fixing roller and a pressing roller pressed against the fixing roller to form a fixing nip therebetween through which the recording medium bearing the toner image passes. As the fixing roller heated by a heater and the pressing roller rotate and convey the recording medium through the fixing nip, they apply heat and pressure to the recording medium, thus fixing the toner image on the recording medium.
After being discharged from the fixing nip, the recording medium separates from the fixing roller by its rigidity. However, if the recording medium is thin and soft, it may not separate from the fixing roller readily and therefore may be wound around the fixing roller. To address this circumstance, a separator may be disposed downstream from the fixing nip in a recording medium conveyance direction to contact and separate the recording medium from the fixing roller.
However, if the thin, soft recording medium bears a solid toner image, the solid toner image, immediately after being discharged from the fixing nip, may not be cooled sufficiently and therefore molten toner of the solid toner image may adhere the recording medium to the separator. To address this circumstance, the separator may be coated with a fluoroplastic layer that facilitates separation of the solid toner image on the thin, soft recording medium from the separator.
However, as the thin, soft recording medium bearing the solid toner image slides over the fluoroplastic layer coating the separator, the solid toner image may be caught in the fluoroplastic layer and therefore the thin, soft recording medium may be tucked. As the solid toner image is caught in the fluoroplastic layer repeatedly, the solid toner image on the tucked recording medium may be deformed into a caterpillar pattern. For example, a section of the solid toner image caught and adhered to the fluoroplastic layer may be damaged while another section of the solid toner image not adhered to the fluoroplastic layer may be clean. Thus, the damaged section and the clean section of the solid toner image, as they are repeatedly produced, may form a faulty caterpillar pattern on the shin, soft recording medium.